Is there any possibility that we lure big free agent this summer?

With Gay aboard, are we having enough money to offer a huge contract to a guy like Al Jefferson? Because if the case is that if we sign one we won't be able to bring back Lowry, well, I'd rather have a star PF lockdown for years to come than having Lowry. But the best would surely be having both. The point of my thread is to know if we have enough cap space too sign a player to a big contract. Thanks. Also I guess we would use our amnesty on Bargs or trade him/same for Kleiza.